1. Field of the Invention
This invention relates to surgical apparatus and methods for polyp management and more particularly to such apparatus and methods for severing and capturing polyps.
2. Description of Related Art
The treatment of polyps and other similar growths in a patient has improved greatly within the last several decades. Polyps are generally collected for histopathological evaluation to determine if they are cancerous. Initially the primary method of treating polyps was major surgery. Now polypectomy procedures are based upon the insertion of a surgical catheter through the working channel of an endoscope. Polypectomy procedures have essentially replaced surgical procedures except when polypectomy procedures are deemed unsuitable, such as when the polyp or polyps to be removed are relatively planar in nature. As used in this application, an endoscope includes a endoscopic or other similar device that is inserted into a patient and that includes a working channel for receiving a surgical catheter or the like and a viewing channel for viewing the interior of a vessel.
The following United States Letters Patent disclose surgical apparatus for polyp management procedures:
U.S. Pat. No. 5,122,147 (1992) Sewell, Jr. PA1 U.S. Pat. No. 4,326,530 (1982) Fleury, Jr.
Sewell, Jr. discloses several embodiments of a polyp marking device and method of using them. FIG. 4 illustrates three generally concentric loops extending from the distal end of the housing. Spacing members contact each loop thereby to position the loops along radially inner, outer and underneath paths. The inner loop 20 has one end fixed to the housing and rachets onto a polyp proximate its base by retraction of a second end extending distally through the housing. The outer loop 23 retracts to grasp the polyp proximate its free end. An intermediate cutting loop has one end fixed in the housing and severs the polyp by retraction of a second end extending through the housing. The inner loop 20 remains attached to the base of the severed polyp.
In another embodiment disclosed by Sewell, Jr. retraction of a cutting loop 21 severs an inner loop 20 from a housing. After such retraction, a forceps device is inserted through the distal end of the housing.- Manipulation of the forceps device enables a physician to capture the severed portion of the polyp. Other embodiments disclosed by Sewell, Jr. disclose clamping devices or jaws having one or more cutting edges for severing a polyp whereby the jaws close to return the severed portion of the polyp. Sewell, Jr. avoids the use of an electric current for cauterizing the severed base by applying a hemostatic agent to the base of the polyp from the inner loop.
Fleury, Jr. discloses a surgical instrument for removing cellular tissue from body cavities. The instrument includes a proximal handle and a distally extending tubular member. A cable passes through the tubular member and includes a self-expanding loop or snare at its distal end. Extension and retraction of the cable enables the loop to enlarge and encompass a polyp and then to contract and sever the polyp. The loop conducts rf electrical current to cauterize the stump of the severed polyp. However, the catheter of Fleury, Jr. does not provide apparatus associated with the instrument itself for capturing the severed portion of the polyp. Rather Fleury, Jr. suggests that other suitable means such as suction associated with a colonscope equipment (i.e., an endoscopic device) captures the severed portion.
Another type of know surgical catheter for performing polypectomy procedures includes a loop or snare disposed at the distal end of the catheter. A basket or net connects to the loop along its defined arc. In use the basket overlies the portion of a polyp to be severed by the loop. Thus, upon severing of the polyp the basket captures the severed portion.
The advantages of such prior art polypectomy procedures in contrast to major surgery are numerous. The advantages generally include reductions in the time and trauma of the operation itself, the time of recovery of the patient, the risk of infection and other problems associated with major surgery. Thus, a surgical catheter device of the prior art generally includes a tubular member extensible through the working channel of an endoscopic device with a cutting loop positioned at the distal end of the tubular member and may include a mechanism for cauterizing the base of a severed polyp.
However, prior art polypectomy devices sometimes are unsuitable for treating certain polyps and are cumbersome and often extend the duration of a procedure unnecessarily.
Some embodiments disclosed by Sewell, Jr., for example, require the use of a separate forceps instrument used in conjunction with the disclosed instrument to retrieve the severed polyp. Generally, Sewell, Jr. discloses a device which requires multiple control wires, three wires in the case of the embodiment of FIG. 4. Furthermore, Sewell, Jr. leaves the inner loop within the body of the patient so that it must be retrieved or otherwise passed from the patient's body.
The device disclosed by Fleury, Jr. also has limited usefulness because it does not include any apparatus for grasping the severed portion. Although some endoscopic devices use suction to extract tissue, the suction, at acceptable levels, is frequently insufficient to hold a severed polyp at the end of the device. Using suction also requires positioning the distal end of the endoscope proximate the polyp. This is not always a simple task. It frequently requires a high degree of skill and dexterity. Should the polyp not be held, it is often difficult to retrieve the severed polyp. Using a forceps device to retrieve such severed portion usually requires the removal of the surgical catheter from the working channel of the endoscope device and insertion of the forceps device. The snare and basket arrangements offer the possibility of retrieving several polyps without removing the apparatus from a patient. However, the weight of the basket depending from the snare tends to deflect the snare and the distal end of the surgical instrument. Consequently it can be difficult to maneuver the snare over a selected polyp. The loops of the basket overlying the snare also can impede snare closure and severance of a selected polyp. Moreover, the movement of the basket loops along the snare tends to dull the snare and makes the severing more difficult. The baskets, being metallic, can contact the snare and bypass current used for cauterizing the severed stump of the polyp. Also, in the case where multiple polyps are collected there is no means to adequately associate the particular polyps collected with the location from which such polyps were taken.
The prior art taken collectively, thus fails to provide an easily used and simply constructed surgical apparatus for effectively and reliably severing and capturing polyps of diverse shapes and sizes. There is no suggestion of a method and apparatus for efficiently and effectively capturing a polyp or severing and capturing successive polyps in a reliable manner and, additionally, being able to associate the position from which such polyps were taken with particular polyps. Further, the prior art devices which require repeated removal and insertion to take a plurality of polyps generally also require repeated removal and insertion of the endoscope, because polyps frequently are larger than the working channel of such endoscopes. Thus, the repeated insertion and removal increases the time for such polypectomy procedures and associated trauma to the patient.